At the mention of hemp, pot and macramé are probably the first things that come to mind. But the history of the material includes a lot more than just a hippie subculture. Hemp is a variety of the cannabis plant, a hearty crop that grows quickly and in many soil conditions. It takes about four months to mature before being harvested, when the plant is cut 2 to 3 cm above the soil and left to dry on the ground for up to four days. Using water, steam and machinery, harvesters separate the fibers, which, along with the seeds, can then be refined into a variety of products, such as rope, paper and fabric – and even building materials and biofuel – making it an incredibly versatile and innovative material.
As one of the earliest domesticated plants, hemp has been cultivated for thousands of years. The first traces were discovered on pottery from China dating back to the Neolithic Age. Many historians believe that pot smoking is what ultimately brought the plant to Europe, where it was first cultivated as a cooking ingredient. It was not used for textiles until the Iron Age. By the 1550s, fibers were being woven into durable ropes used on naval ships, including those of Christopher Columbus. The Spaniards are believed to have brought “hempe” to America during the Spanish Armada. (Although Native Americans in Virginia were also cultivating the crop at the time.) Hemp became a cash crop in the United States in the 1700s and remained significant until the U.S. government legally prohibited cultivation with the Marihuana Tax Act of 1937. Despite illegalization, farmers were encouraged to grow hemp during World War II in order to stop sourcing the Manila hemp crop from Japanese-controlled areas. At that time, hemp was used extensively by the United States for uniforms, canvas and rope. In 1942, the government even produced a short film, Hemp for Victory, promoting the plant as an essential crop for the war efforts.
One of hemp’s most common contemporary uses is cordage in varying tensile strengths, which are then used to make apparel and twine. Pure hemp fabric has a texture similar to that of linen and is very durable and water-resistant. Hemp yarn is made from the stems of the plant, which are processed to dissolve the gum and separate the fibers. The fibers are then processed again and woven into yarn for fabric. Hemp twine and rope is commonly seen in the form of macramé, a method of decorative knotting that became popular in the 1970s (remember those hanging fruit baskets?).
Not to be forgotten is the mighty hemp seed. Its amino acid includes all nine essential oils, making it a “complete” protein. The seeds can be eaten raw, ground, sprouted or made into milk. Hempseed oil (much like linseed oil) solidifies upon exposure to air, creating an effective moisturizing agent in body creams.
One of the most innovative uses of hemp is as an eco commercial building material. Mixed with lime, hemp fibers are made into concrete-like blocks known as hempcrete. Thanks to the fibers’ durability and breathability, hempcrete blocks are an ideal insulation material supported by a wood, brick or steel frame. In 1986, designer Charles Rasetti was the first to use hempcrete when renovating the Maison de la Turque in Nogent-sur-Seine. Since the 1980s, it has appeared more and more frequently in eco-home construction in both Europe and the United States.
Despite hemp’s variety of uses today, many environmental advocates feel that this vital crop has yet to meet its full potential, although the recent re-legalization of industrial cannabis farming could change that. Doug Fine, author of Hemp Bound: Dispatches from the Front Lines of the Next Agricultural Revolution, predicts hemp production will become the country’s next billion-dollar industry and sees it as an untapped resource for energy as a cultivated biofuel. Methyl esters, or bio-diesel, can be made from hemp seed oil and produces less than 1/3 the pollution than petroleum diesel. Who knows what the future of hemp will hold, but it will likely be as impressive as its past.
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Leading image by storebukkebruse via Flickr.